Automatic train-control system



W. K. HOWE.

AUTOMATIC TRAIN CONTROL SYSTEM.

Patented Apr, 4, 1922.

APPLICATION FILED IULYIO, ISIS. 1,41 1,571

3 SHEE fS-SHEET J- vN MN lll 'r W. K. HOWE.

AUTOMATIC TRAIN CONTROL SYSTEM. APPLICATION FILEDIJULYIO, I915.

Patented Apr. 4, 1922.

3 SHEETS-SHEET 2.

W. K. HOWE.

AUTOMATIC TRAIN CONTROL SYSTEM.

APPLICATION FILED IULYIO, 191s.

1,41 1,57 1 Patented Apr. 4, 1922.

3 SHEETS-SHEET 3.

F1 ca- 3.

METNW UNITED sTArss rains? orrics.

WINTI-IROP K. HOWE, OF ROCHESTER, NEW YORK, ASSIGNOE TO GENERAL RAILWAY SIGNAL COMPANY, OF GATEFS, NEW YORK,

A CORPORATION" OF NEW YORK.

AUTOMATIC TRAIN-CONTROL SYSTEM.

To all whom it may comer-a:

Be it known that l, Wmrnnor K. Howe, a citizen of the United States and a resident of the city oi. llochcstcr in the county of Monroe and State of New York, have invented a new and useful Automatic Trains Control System, of which the following is a specification.

This invention relates to improvements in systems for automatically controlling railway vehicles and more particularly to such sys tems in which the movements of the vehicles are controlled, in some appropriate way, by the energization or deenergization of suitable control relays on said vehicles, said energization or deenergization being controlled by devices arranged along the trackway over which the vehicles pass.

One of the principal objects of the invention is to construct and arrange the parts of train control system of the character described so that the operation ofthe system will not be affected if more than one unit equipped with the train control apparatus is included in the train, as for instance ifthe train includes two or more locomotives or motor cars each locomotive or motor car being equipped with the train control apparatus.

A further object of the invention is to devise a simple and reliable train control ap- -paratus, circuits and electrical connections th refor which will properly control the energization of the control relay on each locomotive or motor car included in a train.

regardless of the number of locomotives or motor cars, and regardless of the length of the train or the length of the sections or blocks into which the track is divided.

Other ob'ects and advanta 'es will ap ear as the description of the invention progresses, and the novel features of the invention will be particularly pointed out in the appended claims.

Generally stated, the invention consists 'in' providing a comparatively short control section for each block section which Specification of Letters Patent.

Patented Apr. 4, .1922.

Application filed July 10, 1915. Serial No. 39,181.

In describing the invention in detail, reterence is had to the accompanying drawing, wherein l have illustrated a preferred physical embodiment of my invention, and wherein like characters of reference designate corresponding parts throughout the several views, and in which: 7

Figure l is a diagrammatic illustration of a railway train and a track for said train, and shows the arrangement of the circuits and the parts, associated with the train and with the track, which embody the invention and which are suitable. to control properly the movement otthe train, said figure showing the parts in theirnormal positions and in the condition existing when 'a train approaches one of the ramps or control dev ces along the trackway; Fig. 2 is a diagrammatic illustration similar to Fig. l

and shows the position of the parts of the train control system after part of the train has passed one of the control devices along the trackway, said positions of the parts corresponding to the condition where the train may safely proceed unrestrained by thecontrol system; Fig. 3 is a diagranimatic'illustration similar to Fig. 1 and showing a slightly modified arrangement of the circuits.

lleterrino to the accoinoin l i '1 m ll yin ciavn s, one track rail l. of the railway track is ele tric v continuous, the separate rails therebonded together in any marine; and the other track rail 2 of said railway track is divided into electrically distinct sec tions A, B, C, l) and E in any suitable way, as by insulating joints The sections A. and are or" any appropriate length to obtain the desired spacing of the traih, and will be hereinafter termed block sections. The sections 3 and D are comparatively short and may be as short as convenient,

pry-riding; they are longer than the greatest v lOO to he understood that the same arrangement carried out throughout any des red length of th teach a control section-being located at the. entrance to each blocksection as shown inthe drawing, the direction of normal traific being indicated by an arrow X.

Across the two track rails 1 and 2 at one end of each block section is connected a suit able source of electric current, such as a battery 4, and also connected across the track rails 1 and 2 at the other end of each blocksection by conductors 5 and 6 is a track relay 7. There are two controlling circuits shown in the drawings for the control sec tions BI and D which are the same; and the parts and conductors of the control section D hawe the some reference characters as the corresponding arts and conductors of the control section ,with an exponent added thereto. These track relays 7 together with the track nails 1 and 2 and the batteries 4 constitute the well known normally closed track circuit. as will be understood by those skilled in the art of railway signalling. The track relays 7. are normally energized and their armatureswill be normally held intheir upper position, as shown in Fig. 1. Adjacent to each short control section is a contact rail or-ramp 11, which is supported on the ties of the track but insulated there fiomin any suitable way. Associated with each ramp is a ramp relay 12, and a suit, able source of electric current as a battery 15; which is arranged to be connected to the trackrail 1 and to the corresponding ramp The wires or electrical connections between the different operative parts hereinbefore described willnot be described in detail since these connections and the different operating circuits established will be fully set forth hereinafter in the description of the operation.

The apparatus on the vehicle for controlling" the movement thereof in accordance with the conditions along the trackway,

which are evidencediby the condition of the rampsloca'ted along the track, may be of any suitable construction, but is illustrated as constructed and arranged so that it will not be affected. if a difierence of potential exists between a ramp and a track rail, but.

will be set into operation in case no such difl erence of potential exists. train is shown diagrammatically as com prising two pairsof wheels 16 and 18 and theirconnecting axles 17 and 19 respectively. which represent the wheels of separate cais or locomotives and which are connected by a bar 20 representing the frames of the cars or locomotives. A. bracket or supporting arm 21 of wood or other insulating material issuitably fixed to the axle, journal box or frame of each vehicle, provided with the train control apparatus, and is shown in the drawings as supported on the axle of the rear-pair'of wheels 18; and movably sup ported on this bracket 21 is a shoe 22 which The railway pressed downwardly by a spring 23. This bears against the underside of a contact spring 25 cooperating with contact member 26, so that when said shoe is raised, the contact spring 25 is separated from the contact member 26. The contact spring 25 and the contact member 26 are suitably secured to the bracket 21, which, being of insulating material, serves to insulate said contact spring and said contact member from each other and from the frame of the vehicle. On the vehicle is a control relay 27 having two armatures 28 and 29. One armature 28 of the control relay 27 controls a local'circuit for normally retaining said relay energized from a local source of current, as a. battery 30 carried by said vehicle, when the contact spring 25 is pressed against the contact member 26; and the other armature 29 of said relay controls a local circuit for a device K by means of which the'movement of the vehicle is controlled. This device K may be of any suitable construction which Having described generally the; variousparts constituting the system of train con trol embodying the invention, the operation will be described for difierent cases, in which certain conditions such as may occur in practice are assumed to exist along the trackway.

Referring to Figs. 1 and 2, for the first condition assume the trainunder consideration is in the. blocksection A, as shown in Fig. 1, and is about to enter the control-sec tion B; that the. train has found the road unobstructed and is running without being under the dominance of the train control device K; and that there-is no train in the block section C or inthe block section E.

Since there is notrain in the block. section C, thetrack relay 7 is energized from the track battery 4 and the armatures 8, 9, and 10 of said relay are in. their upper positions.

as shown in Fig. 1. Likewise, the armatures 8 9 and 10 of the track relay 7 of the block section E are in their. upper position,

doctor 48, local battery 15, conductors 43, 44.

and 45, armature 9 of the track relay 7 in itsupper position. conductors 46 and 47 to the ramp 11. As the first pair of wheels 16 enter the control section B a pickup circuit for the ramp relay 12 is established as follows: local battery 15, conductors 43 and 49, ramp relay 12, conductors 50 and 51, armature 10 of the track relay 7 in its upper position, conductor 52, armature 8 of the track relay 7 in its upper position, conductor 53 to the track rail 2 through the wheels 16 and the axle 17 to the traclr rail 1 and along conductor 48 back to the battery 15. It can be seen that the energization of the ramp relay 12 is not possible according to this last mentioned circuit unless the track relays 7 and 7 are energized, that is, unless the block sections O and E are unoccupied. When the ramp relay 12 is energized its armature 13 is raised to close a stick circuit through said relay traced as follows: from the local battery 15, conductors 43 and 49, ramp relay 12, conductors 50 and 54, armature 13 of the ramp relay 12 in its upper position, conductor 55, rail 2 through the wheels 16 and axle 17 to the rail 1 and then along conductor 48 back to the battery 15. Consequently, once the ramp relay 12 is energized and its armature 13 raised said relay will continue to be energized so long as a pair of wheels remains on the control section B. Also, when the ramp relay 12 is energized its armature 14 is raised to establish a shunt around the armature 9 of the track relay 7, so that the circuit hereinbe'fore describechwhich produces a difference of potential between the ramp 11 and the track rail 1, will not be interrupted when the track relay 7 is deenergized and its armature 9 dropped. This shunt is established because, as the vehicle proceeds, the first pair of wheels 16 and the axle 17 will pass into the bloclrsection C and deenergize the track relay 7, as will be understood by those skilled in the art, thus causing the armature 9 of said traclr relay to drop; but since the armature 14 of the ramp relay 12 has been raised a difierence of potential is maintained between the ramp 11 and the track rail 1 by reason of said shunt according to the following partial circuit: from the track rail 1, conductor 48, battery 15, conductors 43, 44 and 56, armaature 14 of the ramp relay 12 in its upper position. and conductors 57 and 4 to the ramp 11. As soon as the last pair of wheels 18 and the axle 19 of the vehicle leave the control section B, the armatures 13 and 14 of the ramp relay will drop and open the circuitwhich maintains a difference of potential between the ramp 11 and the track rail 1 and also interrupt the stick circuit for said ramp relay. 7 1

From the foregoing it can be seen that difference or potential is maintained between the ramp 11 and the track rail 1, prori-c d there 15310 train in the block sections C or E, until the last pair of wheels and axle oi the train pass from the short control section- B, and, consequently, the condition of the ramp 11 is the same when each shoe 22 carried by the different motor cars or locomotires in the train engage said ramp.

As the shoe or plunger 22 strikes the ramp 11 it is raised and the electrical connection makes electrical contact with the ramp 11 and shortly before said shoe has beenraised far enough to separate the contact spring 25 from the contact member 26, current will be supplied to the control relay 27'from the ramp 11 according to the following circuit: battery 15, conductors 43, 44 and 56, armature 14 of the ramp relay 12 in its upper position, conductors Sr and 47 to the ramp 11, shoe 22, conductors 41 and 82, control relay 27, conductors 33 and 42 to the frame 20 through the axles and wheels of the vehicle to the track rail 1 and along conductor 48 back to the battery 15. Consequently, each time the shoe 22 engages a ramp, if there exists a difference of potential between that ramp and the track rail, the control relay 27 will be kept energized and the vehicle may proceed safely.

For the next condition, assume that the vehicle is in the block section A and has had an unobstructed way over which to travel; that there is no train in the block C; but that there is a train in the block section. in this case, a track relay 7 of the block section E will be deenergized and its armature 10 will drop and interrupt the pickup circuit for the ramp relay 12 hereinbe'fore set forth; and, consequently, when the first pair of wheels and axle of the vehicle pass on to the short control section B the ramp relay 12 will not be energized hereinbc iore described. However, until the first wheels of the train enter the block section C, a difference of potential is maintained between the ramp 11 and the track rail 1 according to the circuit hereinber ore set forth, since the armature of the track relay 7 is in its upper position. Then, as the train progresses and its first pair of wheels and axle pass in the block section C, the track relay 7 is deenergized and its armature drops, thereby interrupting the circuit which normally maintains a difference of potential between the i-ainp 11 and the track rail 1. In this way, there is a diiierence ofqiiotential between the ramp 11 and the track rail 1 while the first pair oi wheels and axle are on the short control section B, but when this first pair of wheels and axle pass into the block section C this difference of potential ceases; The shoe 22 as it engages the ramp 11' is raised to interrupt the normally closed circuit through the control relay 27, as here inbefore described, and, during the movement of the train through the control section B, this control relay 27 remains energized; but, as soon as the train enters the block section C, the control relay 27 is deenergized.

, When the control relay 27 is deenergized its armature 28 drops and interrupts the normally closedcircuit through the device K, which controls the operation of the apparatus arranged to control the movement of the vehicle, this normally closed circuit be ing as follows: battery 37, conductor 38, armature 29 of the control relay 27 in its raised osition, conductor 39 through the device and conductor back to the battery 37. The device K may be constructed to shut ofi' thepower and to apply the brakes automatically or may be used to set any suitable train'control apparatus of any other description into operation.

Assuming that the block section E is occu'pied, and that the block section G is not occupied, the ramp 11 may be short enough compared with the length of the control section B and may be located with reference to the insulating joint 3 at the entrance to the block section C so that when the first wheels 16 of the train enter the block section C the first shoe 22 of the train will not yet have reached the ramp 11. In this case, it there is attain in the block section E, no differa enceof potential will exist between the ramp 11 and thetr'ack' rail 2 at any time while the train is passing said ramp, since the presonce of a train in the block E prevents the ramp relay 12 from being energized and since the first pair of wheels and axle of the train enter the block C and deenergize the track relay 7 before the first shoe 22 oi the train makeselectrical contact with the ramp 11. With some types of train control apparatus, however, it may be desirable to energize the control relay 27 when a ramp is passed in every case, whether or not there a. train in the block section E, provided the block section C is unoccupied, and then deenergize the control relay 2'? if the block section 'E is occupied. This requirement maybe satisfied if the ramp 11 is oi? such length and so located with reference to the insulating joints 3 that the first shoe oi the train will make electrical contact with said ramp before the first pair of'wheels and axle of the train enter iutothe block section C, because, whether the block section E is occupied or not, a di'tl'erence of potential is maintained between the ramp 11 and the track rail'2 before the iirst pair of wheels and axle of the train enter into the block C according to the partial circuit cont-rolled by thearmature 9 of the track relay 7, which partial circuit may be traced asfollowsz track rail 1, conductor 18-, battery 15, con

ductors 43, 1 1 and 45, armature 9 of the track relay 7 in its upper position, conductors 46 and 47, to the ramp 11.

Another factor which determines the length and position of the ramps 11 may be noted at this time, that is, the front end of a a ramp must be a greater distance from the insulating joint 3 at the entrance to the block section C than the distance between the last pair of wheels 18' and axle 19 and the contact shoe 22, in order that the shoe will have left electrical contact with the ramp 11 before the last pair of wheels 133 and axle 19 haveleft the control section B.

For the next condition tobe considered, assume that the train under consideration is in the block section A and about to enter the control section B, andthat there is'a train in theblock section C. In this case the train, before it entered the block section A would have been placed under the dominance oi; the train control apparatus, since the presence of the train'i-n the block section C would have set the train control apparatus into operation at the entrance to the block section A, in the same way as the presence of a train in the block section E causes the train control apparatus to be set into opera+ tion when the train entered the blockC, as

hereinbefjore explained The presence of the train in the block section C'requires that the following train should not enter this block section C, unless with great caution and at a low speed; and, consequently, no difference of potential should exist between the ramp 11 andthe track rail 1 so that said following train will not be released from the except that a third armature controlled by the ramp relay 12 is inserted in the conductor designated 52 in Figsl and2, so that said armature 7 5 is included in the pickup circuit of saidzramp relay, said pickup circuit for the modified arrangement shown in Fig. 3 being as follows: battery 15, conductors -13 and 4e, ramp relay 12, conductors 50 and 51, armature 10 of the ramp relay 7% in its upper position, conductor 52, armature 75 of the ramp relay 12 in its upper position, conductor 52", armature 8 of the track relay 7 in its upper position. conductor 53, track rail 2, wheels 18 and axle it), track rail 1 and conductor 48 back to the battery 15. The armature interrupts this pickup circuit for the ramp relay 12 if a pair of wheels and axle of a train occupy the control section D, since a pair of wheels on said control section causes the ramp relay 12 to be energized and its armature 75 to be raised. In this way, the presence of a train on the control section D, as well as on either the block section C or E, will prevent the energization of the ramp relay 12.

Since the presence of the train on the control section D prevents the energization of the ramp relay 12, no difference of potential will exist between the ramp 11 and the track rails after the first pair of wheels and axle enter the block section C and the train control device K- will be set into operation. Also, the pickup circuit for the ramp relay 12 is interrupted if the relay 12 is energized for any reason, as for instance by stray current; or it the armatures of the relay 12 do not drop after a train has passed the control section D, the device K on the following train will beset into operation when said following train enters the block section C. From the foregoing it can be seen that the third armature 75 added to the ramp relay 12 provides additional safeguards against improper operation of the system.

In the specific embodiment of the inven tion shown and described, contact rails or ramps are used; but it is to be understood that the combination of circuits and controlling means constituting my invention is not limited in its application to ramps and may be used in connection with other suitable devices or appliances, the function of which is to transmit some form of a 0011- trolling impulse to a passing vehicle or train, these equivalent devices or appliances falling within the scope of my invention being conveniently referred to as impulse devices, impulse transmitting means, and the like.

Although I iave particularly described the construction of one physical embodiment of my invention, and explained the operation and principle thereof; nevertheless, I desire to have it understood that the form selected is merely illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. In an automatic train control system, in combination: a trackway adapted for moving vehicles and comprising electrically isolated block sections, a comparatively short control section at the entrance to each of said block sections and electrically isolated therefrom; an insulated ramp positioned near the entrance to each of said block sections; a relay associated with each ramp for completing a circuit which establishes a ditterence of potential between said ramp and the track rails; an operating circuit for said relay terminating at the rails of the corresponding short control section; a stick-up circuit for said relay also terminatingat the rails of said control section and controlled by the relay itself; and means responsive to the presence of a vehicle on either of the two block sections in advance for breaking said relay operating circuit.

2. In an automatic train control system, in combination; a trackway adapted for moving vehicles and comprising electrically isolated block sections, a. comparatively short control section at the entrance to each of said block sections and electrically isolated therefrom; an insulated ramp positioned near the entrance to each of said block sections; a relay associated with each ramp for completing a circuit which establishes a difference of potential between said ramp and the track rails; an operating circuit for said relay terminating at the rails otthe corresponding short control section; a stickup circuit for said relay also terminating at the rails of said control section andcontrolled by the relay itself; and means responsive to the presence of a vehicle on either of the two blocksectionsin advance or the next short control section in advance for breaking said relay operating circuit.

3. In an automatic train control system, in combination: a trackway adapted for mov ing vehicles and comprising electrically isolated block sections, a comparatively short control section at the entrance to each of 1 said block sections and electrically isolated therefrom; an insulated ramp positioned near the entrance to each of said block sections; a source of current and a relay constituting' a track circuit for each of said block sections; a circuit controller operated by each relay and having pairs of cooperating contacts which are closed when said relay is energized; a circuit associated with each block section including one pair of contarts of the circuit controller or the track relay of that block section for maintaining a difference of potential. between said ramp at the entrance of that bloclr section and the track rails; a circuit associated'with each track relay for shunting said last-mentioned pair of contacts thereof, and means responsive to the presence of a vehicle on the corresponding short control section for closing its corresponding shunting circuit when neither of the next two block sections in ad- Vance is occupied.

4. In an automatic train control system, in combination: a trackway adapted. for moving vehicles and comprising electrically 1 yes truncate each of sai isolated bloc-Jr sections, a comparatively.

short control section at the entrance to each of said block sections and electrically isolated therefrom; an insulated ramp posi- 5 tioned near the entrance to each of said block sections; a source of current and a relay constituting a track circuit for each of said block sections; each of said track relays having front contacts which are closed when 110 said relay is energized; a circuit associated with each block section including a front contact of the corresponding track relay for maintaining a difference of potential between said ramp at the, entrance of that block section and the track rails; a circuit for shunting said last mentioned front contactiof said track relay; a ramp relay having cooperating contacts which are included in the shunting circuit of the corresponding '20 block and whichare closed when said ramp relay is energized; and an operating circuit for each ramp relay terminatingat the rails vof the corresponding short control section :and including other front contacts of the track relays of the next two block sections in advance.

5. In an automatic train control system, in combination: a trackway adapted for moving vehicles and con'iprising electrically isolated block sections, a comparatively short control section at the entrance to each of said block sections and electrically isolated therefrom; an insulated ramp positioned =near'the entrance to each of said block sections; s. source of current and atrack relay constituting a track circuit for each of said block sections; each track relay having front contacts which are closed when said relay is energized; a circuit associated with each of 40 said block sections which includes a front contact of the correspondingtrack relay for maintaining a difference of potential be tween the corresponding ramp and the track rails; a circuit-for shunting the last-mentioned front contact of said track relay; a

rrunprelay having cooperating contacts inchided in the shunting circuitof the correspending block, which are closed when said ramp relay iS energized: each ramp relay having a hack contact which isopci'ied when saidrelayis energized: and an operating ciricuit for each ramp relay terminating at the railsiof the corresponding short control section and including the contacts of the track relays of the next two block sections in ad vance and said back contact of the ramp rclayof the next control section ll'l'illliflllcc.

6. In an auton'iatic train control system, in

combination: a trackway adapted for-moving 1H0 vehicles and comprising electrically isolated block sections, a comparatively short control section at the entrance to each of said block sections and electrically isolated therefrom;

"an insulated ramp [positionednear the en block sections ;two aircuits for establishing a difference of potential between said ramp and the track rails,

control section at the entrance to'each of said block sections and electricallyisolated there from; an insulated ramp positioned near the entrance to each of said block sections; two circuits for establishing a difference of potential between said ramp and the track mils, one of said circuits being controlled by the presence of a train on the corresponding short control section, and the other being controlled by the presence of a train on the corresponding block section, and means responsive'to the presence of a train on either the corresponding block section or the next block section in advanceorthe next control section in advance :for preventing said firstmentioned circuit from being established.

8. In an automatic train control system, in combination: a track for moving vehicles divided into blocks each having a track relay; a comparatively short electrically isolated control section at the entrance to each block; an impulse device associated "with each block; a normally closed controlling circuit for each impulse device governed by the tracklrelay of the corresponding block and interrupted when that block is occupied; and normally ineffective means for each block controlled by the track relay ihcreof and'having itsoperation determined byxthe presence of a train on the adjacent ccntrol section for establishing said con trolling circuit independently of the control of said circuit by the track relay of the litil'l'CSl JOilfll[lg block. V

i). in an automatic train control system, in (f(' llll)lllkttl()lli a train and a truck therefor divided into blocks; a comparatively short electrically isolated control section at the entrance to each block; an impulse device associated with each block; a normally open controlling circuit for each impulse device; means for closing said circuit so long as the corresponding control section is occu pied. provided the corresponding block and the next block in advance are not occupied; and means on the several vehicles of train for cooperating with said impulse devices.

10. In :an automatic train control eystemfiao v trance to each in combination: a track divided into blocks provided with track circuits; 'a comparatively shortelectric lly isolated control section at the out anceto iach block; an impulse device associated with each block; a circuit for controlling each impulse device; and means for controlling said circuit, said means being initially rendered effective when the corresponding control section is occupied and the corresponoing block and the block next in advance are not occupied, said means after being initially rendered effective being maintained eli ective so long as the corresponding control section is occupied by a portion of a train.

11. In an automatic train control system tor railroads in combination: a train and a track therefor divided into blocks each having a normally closed track circuit; a comparatively short control section at the enblock; an impulse device as sooiated with each block and arranged to transmit impulses to the vehicles of a pflSSlliQf t'ain both )rior to and subsequent to the entrance of the train into such block, the safety cont-rolling condition of each impulse device being normally dependent upon the track circuit of the corresponding block; and means having its initial operation dependent upon the presence of a train on the track circuits ol the correponding block and the next block in advance for causing the safety cont-rolling condition of each im pulse device to exist alter the entrance of the train into the corresponding control section and so long as such train occupies said control section.

12. In an automatic train control systolic. for railroads, in combination: a train and a track therefor divided into blocks each having a normally closed track circuit; a comparatii 'ely short control section at the entrance to eachbloclc; a contact ramp associatcdwith each block and arranged to be engaged by the shoes on the Yehic i passing train both prior to andfsubsequent to the entrance of a train into said block] said ramp being in its safety controlling condition when energir ied; a circuit con trolled by the iracl: circuit of th corre spending block tor normally energizing each cramp; and normally inactive means associated with each ramp and liming its initial. operation dependent'upon the presence ol? circuits of the cone :uiionding block and the next blocl: in ad i'tliltl for causing energization oi that ramp upon the entrance ot a train into the corresponding control section and for continuing such encrgization until such train has passed oil of the rails of said control section.

13. In an automatic train control system for railroads, in combination: a train and a track therefor divided into blocks each having a normally closed track circuit; a

conuniratirely short control section at the entrance to each block; an impulse device associated with each block and arranged to transmit impulses to the vehicles ol a passing train both prior to and subsequent to the entrance oi? the train into said block;

' circuit associated with each -v device for placing that device in its saiety controlling condition, said controlling circuit being governed by the front contact of the traclt relay of the corresponding block a normally open shunt tor said front contact of each track relay; means associated with each impulse derice and having its initial ope ation dependent upon the presence of a train on the track circuits of the corresponding block and the next block in advance for closing said shunt circuit 13031 the entrance a train into the corresponding controlling szction and for main taining it closed until such train h'as passed out of said control section.

let. in an automatic train control system for railroads, in combination: a train and a track therefor divided into blocks each having a. normally closed track circuit; a comparatively short control section at the entrance to each block; an impulse device associated with each block and arranged to cooperate with elements on the vehicles of a passing train both prior to and subsequent to the entrance of a train into saiilblock, each impulse device being in its safety controlling condition Whensupplied with cur rent; a circuit controller governed by the track circuit of each block and closed when that block is not occupied; a circuit -lor normally supplying current to each impulse device including the circuit controller of the track circuit of the corresponding block; a normally open shunt for each circuit controller; a stick relay for closing said shunt when energized; an energizing circuit for each stick relay having its continuity depcndei'itupon the track circ 'lits of the corresponding clock and the n-ex'tblock in advance being unshunted and adapted to be established by the presence of a pair of Wheels on the corresponding control section; and means tor-nuiintaining each stick relay energized after it hosbeen initially energized so long as the corresponding control. section o cupied by a pair of wheels.

l5. in an automatic train control systen'i For railroads in combination: a t am and a track there-For divided into blocks each having a normally closed track circuit; a comparatively short control section at the en trance to each block; an impulse device asso ciated With each block and arranged to cooperate with elements on the vehicles of a passing train both prior to and subsequent to the entrance of the train into the corresponding block eachimpulse device being adapted to assume its safety controlling condition when supplied with current; means controlled by the track circuit of the corresponding block for normally supplying current to each impulse device; and means ini' tially controlled by the track circuits of the corresponding block and the next block in advance and adapted to be rendered active by the entrance of a pair of wheels into the corresponding control section for independontly supplying current to each impulse device, said last mentioned means after its initial operation has been determined, being maintained in its operated condition so long as a pair of Wheels is on the corresponding control section.

16. In an automatic train control system 'for railroads, in combination: a train and a track therefor divided into blocks each having a normally closed track circuit; an insulated rail section at the entrance to each block; an impulse device associated with each block and adapted to assume a safety controlling condition when supplied with current; a normally open controlling circuit for each impulse device including a source of current and adapted when closed to cause the corresponding impulse device to assume its safety controlling condition: and normally inactive means having its initial operation dependent upon the presence of a train on the track circuits of the corresponding blockand the next block in advance for closing said controlling circuit when a pair of wheels occupied the corre.

sponding insulated rail section and for maintaining it closed so long as said rail sectlon is occupied.

17. In an automatic train control system for railroads, in combination: a track divided into blocks each having a'normally closed track circuit; a comparatively short control section at the entranceto each block; an impulse device associated with each block and normally in its safety controllingcondition when the corresponding block is unoccupied; a relay associated witheach impulse device and adapted when energized to cause that im ulse device to assume its safety controlling condition independently of the subsequent shunting of the track circuit of the corresponding block; and an energizing circuit for each of said relays re spon'sive to the presence of a pair of wheels on the corresponding control section and controlled by the track circuits of the corresponding block and the block next inadvance. V

18. In an automatic train control system "For railroads divided into blocks each having a normally closed track circuit and a comparatively short insulated rail section at the entrance thereto, the combination with an impulse device associated with each block and adapted toltransmit controlling impulses to passing vehicles; of automatic train controlling means on the passing vehicles including a relay influenced by the controlling condition 01 said impulse devices along the track, said relay being either re-energizedor maintained energized by an impulse device in the safety controlling condition, and being (lo-energized or maintained tie-energized by an impulse device in the danger controlling condition; and means for causing the con trolling condition of each impulse device to be dependent in succession upon the track circuit of the corresponding block, and then upon the track circuit of both the corresponding block and the next block in advance, said mean also acting to maintain said impulse device in the same existing controlling condition after a passing train enters the corresponding blockrand so long as any part of such train remains on theicorresponding insulated rail section.

19. In an automatic train control system for railroad having blocks provided with normally closed track circuits, the combination with an impulse device associated with each block; of automatic train control means on the passing vehicles including a relay influenced by the controlling condition of said impulse devices, said relay being either reenergized or maintained energized by an impulse device in the safety controlling condition and being (lo-energized or maintained de-energized by an im ulse device in the danger controlling condlt-ion; and means for causing the controlling condition of each impulse device. to be dependent in succession upon the track circuit of the correspondin block, and then upon the track circuits 0 both the corresponding block and the next block in advance.

20. In an automatic train control system for railroads having blocks provided With normally closed circuits, the combination with an impulse device at the entrance to each block; of automatictrain control means on the passing vehicles including a control device adapted to be influenced by the controlling condition of said impulse devices, said control device being rendered inactive or maintained inactive by the safety controlling condition ot an impulse device, and being rendered active or maintained active by its danger controlling condition; and means responsive to the presenceof a pair of wheels of a train adjacent to an impulse device and controlled-by the track circuits of both the corresponding block andthe next block in advance for placing that impulse device in the safety controlling condition when said blocks are not occupied, said means also acting to maintain such safety controlling condition until all pairs of Wheels of the train have passed that impulse device, regardless of the entrance of such train into the correspondin block.

WINTHROP HOWE. 

